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Poster: Mandojammer Date: Jan 15, 2009 11:00am
Forum: GratefulDead Subject: Submarine Lesson #3 ICEX Pictures

More Arctic mission pics. The 'sunset' picture was taken around 11 PM - in the summer of course. It was -45.

I like the pic with the bear peering into the water near the rudder.

The picture of the three bears walking around the bow is also pretty interesting. They must be thinking "Man that is one big ass seal. If we can pull this off we'll eat like kings."

If you look closely at the picture you can see the Main Ballast Tank vent cover in the lower left (the round thing flush with the deck). The vertical protrusion is an underwater acoustic intercept sonar hydrophone. If you look closely at the bottom center you can see a small blister on the hull. That is the fairing for one of the boat's towed array sonars. We string a series of hydrophones several thousand feet behind the ship to search for bad guys. By putting it back behind the ship, we greatly reduce own ship ambient noise which can reduce the ability to pull threat data out of the field of noise the ocean generates. Reducing the own ship noise contribution can sometimes boost the SNR by several dB and can make the difference between detection or not. The ocean is extremely noisy - carpenter fish, shrimp and of course whales. I've heard shrimp as loud as 100 dB. One very cool phenomenon you can observe is the tectonic rumble of the earth's crust. You have to configure the sonar bandwidth and frequency spectrum you are sampling in specifcally to hear it but it is pretty cool. It sounds like a continuous avalanche heard from far off - down in the 22 Hz portion of the spectrum.

More to follow. Lesson #4 will be the USS SAN FRANCISCO after her seamount collision. We were damn lucky we didn't lose the ship.

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Poster: clashcity Date: Jan 15, 2009 5:07pm
Forum: GratefulDead Subject: Re: Submarine Lesson #3 ICEX Pictures

Seriously, badass.